Process of treating ores in the manufacture of rustless steel



Patented. Oct. 13, 1931 UNITED STATES PATENT OFFICE CHARLES rum/r, or menu, rmmsnvam, ASS-IGNOB or ,ONE-HALFY TO PETER sammas, or wasnmeron, msrarcr or COLUMBIA PROCESS OF No Drawing.

The present invention relates to the treatment of ores, whereby certain constituent parts of the .ores become concentrated and certain othercons tituent parts of the ores beganese, lime, soda, sulphur compounds come partially removed, so that the relative ratio of the second class of metals, to the first class of metals, is increased.

The process is applicable to many ores containing two or more difierent kinds of metal, and a particular ore to which I call attention-is a Cuban ore, consisting largely of;

ferric oxide in a hydrated condition. An analysis of this ore showed one sample to contain about-46%. of iron, about 2% of silica, about 8% of alumina, about 1.7 of chromium, about 0.5% of nickel, and about 12% of water.

ore contained around 46.7 5% of iron, 6% of silica, 12% of alumina, 1.85%of chromium, 1% of nickel and around 11% of water. The ores also contained small amounts of mand potassium; A similar ore found in a diife'rent location is known as laterite. These ores are cited merely as examples of ores which may be treated in accordance with the ore for. theproduction o 1 ig iron resent invention. Chromium and nickel, as

ound in these ores are found to be less readily chloridized, than is iron, and the process accordingly embraces the-ste of heating the ore. to a temperature at whic chloridization of the ore can be effected, say by means of chlorine gas or a gas 'contaming chlorine gwhich may be in the elemental condition if I esired) although it is possible to efiect the chloridization y probably less advant usl Reducin t e whlch stainless steel can read be produced b a direct method, is not readil lyrpossible for t ereason that the content of c omium and nickel in the ore is i'nsuflicient and it is not always readily possible to enrich the pig iron in chromium and nickel, to the-required extent. I

. -Accordingly I V 've the following method by which this res t can readily secured.-

A quantity of ore is laced in a retort, and

Another somewhat similar other methods, althou hv TREATING. OBES IN THE MANUFACTURE OI RUSTLESS STEEL I Application filed September 28, 1930. Serial No. 484. HD

.method set forth. Under these conditions, a

substantial portion of the iron content of the ore will vaporize, and after continuing the treatment for about an hour and'a half, it

will be found that there has been a material change in the ratio between iron present and nickel and chromium present, due to the volatili'z ation of iron chloride from the ore. It will be understood that the volatilization is somewhat more rapid at temperatures substantially higher than here indicated, but

there is likely to be more loss of the chromium and nickel, by volatilization. In this connection it may be noted that both chromium and nickel are capable of conversion into chlorides and-vaporization, in the form of chlorides, but under the preferred temperature conditions,-the material vaporized will be largely iron, in the form of ferric chloride,

these being ad ed either in the form of crude ores or concentrates. For example after the chloridization treatment, other chromium ores can be added to the ore, and other nickel ores can be added. I also contemplate adding ores of other metals such as zirconium which are useful in the production of alloy steels of the kind referred to. Ordinarily I would not recommend adding'the zirconium ores to the initial ore prior to chloridization, for the reason that the chloridization treatment might carry away a substantial proportion of the zirconium, which of course as recognized is relatively high riced material.

After the c oridization treatment and after the addition of other ores as above indicated, the charge ma be smelted in a suitable furnace, such asia blast furnace, to obtain a pig iron having a comparatively high percentage of chromium and nickel, and optlonally zirconium, from which a high grade ofrustless steel can be made. It Will be under- 5 stood that any of the usualblast furnace procedures can be employed, such as first briquetting the ores if desired, the -use of suitable amounts of fuel and fiuxing'agents,vsuch as lime and the like, or the ore could be reduced 1 in another manner instead of in a blast furnace. During the smelting operation, some of the oxide of iron, most of the silica and alumina and perhaps small quantities of theoxides of chromium and nickel might pass into the slag, but the main portions of the chromium and nickel, together with'a' part of the iron would be reduced to the metallic state, and the zirconium if employed would likewise be reduced to the metallic condition, and would enter the pig iron. 7

It will bQilllldQISilOOd that the preferred temperature to be employed in this particular case naturally depends to a considerable ex- 1 tent upon the precise ore'under treatment, and experimental runs should be made with each batch of ore to determine the most advanta-' 'gcous temperature for that particular ore.. lVith the Cuban ore according to the first analysis above given', a temperature-of about 3 480 to 490 Crwill be found most satisfactory 7 Iclaim: '7 W A process which vcomprises heating 'an-ore* containing iron-in large proportion, and chro-" mium and nickel in far smaller quantities, which comprises heating said ore to' a tem perature at which ferric chloride is readily 7 volatile, and contactin the ore with a stream 'of gases containing ree chlorine until the iron content of the ore has been substantially 4o lowered and the chromium and nickel content of the ore has been substantially increased and thereafter adding further-quantities of chromium and nickel-ores, and adding zireonium ore, then reducing the material in a 5 furnace to produce a pigiron whichris partic ula'rly suitable for the production of alloy steels. g a

In testimony whereof I afiix' m signature.

CHARLE 'HART.

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